U.S. patent number 7,223,195 [Application Number 11/507,060] was granted by the patent office on 2007-05-29 for multispeed power tool transmission.
This patent grant is currently assigned to Black & Decker Inc.. Invention is credited to Michael C Bowers, Todd A Hagan, Rodney Milbourne, Christine Potter.
United States Patent |
7,223,195 |
Milbourne , et al. |
May 29, 2007 |
Multispeed power tool transmission
Abstract
A portable power tool with a housing, a motor having a motor
output member, a driven member and a transmission. The
transmission, which is located in the housing, is configured to
receive a rotary input from the motor output member and to produce
a rotary output that is transmitted to the output spindle. The
transmission has a plurality of planetary transmission stages, each
of which including a ring gear, a planet carrier and a plurality of
planet gears that are supported by the planet carrier for meshing
engagement with the ring gear. The transmission further includes at
least one member that may be configured in a first condition, which
renders at least one of the planetary transmission stages operable
in an active mode, and a second condition, which renders at least
one of the planetary transmission stages operable in an inactive
mode. The transmission is operable in at least three overall speed
reduction ratios.
Inventors: |
Milbourne; Rodney (Abington,
MD), Potter; Christine (Baltimore, MD), Hagan; Todd A
(Windsor, PA), Bowers; Michael C (Littlestown, PA) |
Assignee: |
Black & Decker Inc.
(Newark, DE)
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Family
ID: |
35056265 |
Appl.
No.: |
11/507,060 |
Filed: |
August 18, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060281596 A1 |
Dec 14, 2006 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10792659 |
Mar 3, 2004 |
7101300 |
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10384809 |
Mar 10, 2003 |
6984188 |
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09964078 |
Sep 26, 2001 |
6676557 |
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60263379 |
Jan 23, 2001 |
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Current U.S.
Class: |
475/298; 173/217;
475/264; 475/263; 173/47; 173/216; 475/265; 475/279; 475/286;
475/299; 475/305; 475/317; 475/330; 475/275; 173/178 |
Current CPC
Class: |
B23B
45/008 (20130101); B23Q 5/142 (20130101); B25B
21/00 (20130101); B25B 23/14 (20130101); B25F
5/001 (20130101); B25F 5/006 (20130101); B25F
5/02 (20130101); F16H 3/64 (20130101); F16H
63/18 (20130101); F16H 2200/2035 (20130101); F16H
2200/0034 (20130101); F16H 2200/0039 (20130101); F16H
2200/0043 (20130101); F16H 2200/201 (20130101); B23B
2260/11 (20130101) |
Current International
Class: |
F16H
3/44 (20060101) |
Field of
Search: |
;475/298,286,264,263,279,270,275,305,317,320,330
;192/56.61,17R,3.52,48.91 ;173/178,216,217,47,48 ;464/38 |
References Cited
[Referenced By]
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60-34 275 |
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62-224 584 |
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62224584 |
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JP |
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63101545 |
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JP |
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63-96 354 |
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JP |
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WO 97/33721 |
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WO |
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WO 99/16585 |
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Apr 1999 |
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WO |
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Other References
FESTO Catalogue 96/97, pp. 1 through 4 and 10 through 19. cited by
other .
FESTOOL Festo Tooltechnic CDD 9,6ES Exploded View (457 895 /
10.99). cited by other .
Tools of the Trade Online: Stop The Pain (Spring 1998). cited by
other.
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Primary Examiner: Le; David D.
Attorney, Agent or Firm: Harness, Dickey & Pierce,
P.L.C.
Parent Case Text
PRIORITY & CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No.
10/792,659, filed Mar. 3, 2004 now U.S. Pat. No. 7,101,300 which is
a continuation-in-part of U.S. application Ser. No. 10/384,809
filed Mar. 10, 2003 (now U.S. Pat. No. 6,984,188), which is a
divisional of U.S. application Ser. No. 09/964,078 filed Sep. 26,
2001 entitled First Stage Clutch (now U.S. Pat. No. 6,676,557),
which claims the benefit of U.S. Provisional Application No.
60/263,379, filed Jan. 23, 2001. Other features of the present
disclosure are discussed and claimed in commonly assigned U.S. Pat.
No. 6,431,289 (Multi-Speed Power Tool Transmission); U.S. Pat. No.
6,857,983 (First Stage Clutch); U.S. Pat. No. 6,502,648 (360 Degree
Clutch Collar); and U.S. Pat. No. 6,805,207 (Housing with
Functional Overmold Member) and commonly assigned U.S. application
Ser. No. 10/953,699 (Multispeed Power Tool Transmission); and Ser.
No. 11/237,112 (Multispeed Power Tool Transmission); Ser. No.
10/931,602 (Housing with Functional Overmold Member); Ser. No.
10/931,604 (Housing with Functional Overmold Member); and Ser. No.
10/915,698 (Housing with Functional Overmold Member).
Claims
What is claimed is:
1. A portable power tool, comprising: a housing having a first
portion and a second portion, the first portion defining a handle
for carrying the portable power tool; a motor received in the
second portion of the housing, the motor having a motor output
member; a trigger coupled to the housing, the trigger being movable
to activate the motor; a driven member; and a transmission assembly
coupled to the housing and configured to receive a rotary input
from the motor output member and to produce a rotary output that is
transmitted to the driven member, the transmission assembly having
a plurality of planetary transmission stages, each of the planetary
transmission stages including a ring gear and a set of planet gears
meshingly engaged with the ring gear, wherein at least one member
of the transmission assembly may be configured in a first
condition, which renders at least one of the planetary transmission
stages operable in an active mode, and a second condition, which
renders at least one of the planetary transmission stages operable
in an inactive mode, wherein the transmission assembly is operable
in at least three overall speed reduction ratios, wherein at least
three planetary transmission stages transmit torque in sequence
between the motor output member and the driven member in each
overall speed reduction ratio and wherein the ring gear associated
with each of the at least three planetary transmission stages is
not meshingly engaged to the set of planet gears of another of the
at least three planetary transmission stages; wherein the
transmission assembly further includes a speed selector having only
one switch member, the only one switch member forming a portion of
an exterior of the portable power tool and being slidably movable
between a first position, a second position and a third position,
the at least one member of the transmission assembly being coupled
to the only one switch member and at least one of the plurality of
planetary transmission stages, the at least one member of the
transmission assembly being movable in response to movement of the
only one switch member to cause the plurality of planetary
transmission stages to cooperatively operate in one of the overall
speed reduction ratios that corresponds to an associated one of the
positions in which the only one switch member is disposed; wherein
at least two of the planetary transmission stages are operable in
the active mode for performing a speed reduction and torque
multiplication operation and in at least one of the at least three
overall speed reduction ratios.
2. The portable power tool of claim 1, wherein the at least one
member includes a portion that may be selectively engaged to an
associated one of the ring gears to thereby inhibit relative
rotation between the associated one of the ring gears and the
portion.
3. The portable power tool of claim 2, wherein the portion includes
at least one of a pin, a ball and a roller.
4. The portable power tool of claim 2, wherein the transmission
assembly includes a planet carrier that supports at least one of
the sets of planet gears.
5. The portable power tool of claim 4, wherein the at least one
member includes a plurality of teeth formed onto the planet carrier
and a plurality of mating teeth formed on at least one of an
associated one of the ring gears and an associated one of the sets
of planet gears and wherein the teeth and the mating teeth engage
one another to facilitate co-rotation of the associated one of the
ring gears and the planet carrier.
6. The portable power tool of claim 5, wherein the mating teeth
extend axially from the at least one of the associated one of the
ring gears and the associated one sets of planet gears and
meshingly engage the teeth when the planet carrier and the at least
one of the associated one of the ring gears and the associated one
of the sets of planet gears are abutted against one another.
7. The portable power tool of claim 5, wherein the mating teeth are
formed about an inner diameter of the associated one of the ring
gears and wherein both the teeth and a plurality of teeth formed on
the associated one of the sets of planet gears meshingly engage the
mating teeth when the planetary transmission stage that includes
the associated one of the ring gears is operated in the inactive
mode.
8. The portable power tool of claim 1, wherein the at least one
member includes an annular structure that may be translated between
a first position and a second position, the annular structure being
configured to non-rotatably couple an associated one of the ring
gears to the housing when positioned in the first position so that
the planetary transmission stage that includes the associated one
of the ring gears is operated in the active mode.
9. The portable power tool of claim 8, wherein the transmission
includes a planet carrier that supports at least one of the sets of
planet gears and wherein when the annular structure is positioned
in the second position the annular structure couples the associated
one of the ring gears to the planet carrier such that the
associated one of the ring gears and the planet carrier
co-rotate.
10. The portable power tool of claim 8, wherein the annular
structure may be translated independently of the associated one of
the ring gears.
11. The portable power tool of claim 8, wherein the transmission
includes a planet carrier that supports at least one of the sets of
planet gears and wherein the annular structure frictionally engages
the planet carrier when the annular structure is positioned in the
second position.
12. The portable power tool of claim 8, wherein the transmission
includes a planet carrier that supports at least one of the sets of
planet gears and wherein the annular structure includes a plurality
of teeth that meshingly engage a plurality of mating teeth formed
on the planet carrier when the annular structure is positioned in
the second position.
13. The portable power tool of claim 12, wherein the mating teeth
are formed on a side of the planet carrier.
14. The portable power tool of claim 12, wherein the mating teeth
are formed on an axial end of the planet carrier.
15. The portable power tool of claim 8, wherein the annular
structure includes a locking member that engages the housing to
thereby inhibit rotation of the annular structure relative to the
housing.
16. The portable power tool of claim 15, wherein the locking member
on the annular structure includes at least one feature that is
selected from a group consisting of pins and teeth.
17. A portable power tool, comprising: a housing having a first
portion and a second portion, the first portion defining a handle
for carrying the portable power tool; a motor received in the
second portion of the housing, the motor having a motor output
member; a trigger coupled to the housing, the trigger being movable
to activate the motor; a driven member; and a transmission coupled
to the housing and configured to receive a rotary input from the
motor output member and to produce a rotary output that is
transmitted to the driven member, the transmission having a
plurality of planetary transmission stages, each of the planetary
transmission stages including a ring gear and a set of planet gears
meshingly engaged with the ring gear, wherein at least one member
of the transmission may be configured in a first condition, which
renders at least one of the planetary transmission stages operable
in an active mode, and a second condition, which renders at least
one of the planetary transmission stages operable in an inactive
mode, wherein the transmission is operable in at least three
overall speed reduction ratios, wherein at least three planetary
transmission stages transmit torque in sequence between the motor
output member and the driven member in each overall speed reduction
ratio and wherein the ring gear associated with each of the at
least three planetary transmission stages is not meshingly engaged
to the set of planet gears of another of the at least three
planetary transmission stages; wherein the at least one member
includes an idler gear that may be selectively engaged when the
planetary transmission stage that includes the associated one of
the ring gears is operated in the inactive mode, the idler gear
having a rotational axis that is not coincident with a longitudinal
axis of the transmission.
18. The portable power tool of claim 17, wherein the transmission
includes a planet carrier that supports at least one of the sets of
planet gears and wherein the idler gear includes a plurality of
teeth that engage mating teeth that are formed on the planet
carrier regardless of whether the planetary transmission stage that
includes the associated one of the ring gears is operated in the
active mode or the inactive mode.
19. The portable power tool of claim 18, wherein a portion of the
plurality of teeth on the idler gear engage one or more teeth that
are formed on the associated one of the ring gears when the
planetary transmission stage that includes the associated one of
the ring gears is operated in the inactive mode.
20. The portable power tool of claim 17, wherein the idler gear
includes a plurality of teeth that engage mating teeth that are
formed on the associated one of the ring gears regardless of
whether the planetary transmission stage that includes the
associated one of the ring gears is in the active mode or the
inactive mode.
21. The portable power tool of claim 20, wherein the transmission
includes a planet carrier that supports at least one of the sets of
planet gears and wherein the idler gear is moved into a position
where the teeth of the idler gear also engage a plurality of teeth
formed on the planet carrier when the planetary transmission stage
that includes the associated one of the ring gears is operated in
the inactive mode.
22. The portable power tool of claim 17, wherein the transmission
includes a planet carrier that supports at least one of the sets of
planet gears and wherein the idler gear is movable into a position
where it co-engages the associated one of the ring gears and the
planet carrier when the planetary transmission stage that includes
the associated one of the ring gears is operated in the inactive
mode.
23. The portable power tool of claim 22, wherein the at least one
member further includes a portion that may be selectively engaged
to the associated one of the ring gears to thereby inhibit relative
rotation between the associated one of the ring gears and the
portion when the planetary transmission stage that includes the
associated one of the ring gears is operated in the active
mode.
24. A portable power tool, comprising: a housing having a first
portion and a second portion, the first portion defining a handle
for carrying the portable tool; a motor coupled to the second
portion of the housing, the motor having a motor output member; a
driven member; and a transmission assembly coupled to the housing
and configured to receive a rotary input from the motor output
member and to produce a rotary output that is transmitted to the
driven member, the transmission assembly having a reduction gearset
assembly, the reduction gearset assembly includes a plurality of
ring gears, a plurality of planet carriers and a plurality of sets
of planet gears, a first one of the sets of planet gears being
supported by a first one of the planet carriers and meshingly
engaging a first one of the ring gears, a second one of the sets
of-planet gears being supported by a second one of the planet
carriers and meshingly engaging a second one of the ring gears, the
driven member being coupled for rotation with the second one of the
planet carriers, wherein at least one member of the transmission
assembly may be configured in a first condition, which renders at
least one of the planetary transmission stages operable in an
active mode, and a second condition, which renders at least one of
the planetary transmission stages operable in a mode other than the
active mode, wherein the transmission is operable in at least three
overall speed reduction ratios, and wherein at least three
planetary transmission stages transmit torque between the motor
output member and the driven member in each overall speed reduction
ratio, wherein each overall speed reduction ratio inchides an input
stage, an output stage and at least one intermediate stage between
the input stage and the output stage, the input stage receiving
rotary input, the output stage outputting the rotary output, the at
least one intermediate stage drivingly connecting the input stage
and the output stage, and wherein the ring gear associated with
each of the at least three planetary transmission stages is not
meshingly engaged to the planet gears of another of the at least
three planetary transmission stages; wherein the transmission
assembly further includes a speed selector having only one switch
member, the only one switch member forming a portion of an exterior
of the portable power tool and being slidably movable between a
first position, a second position and a third position, the at
least one member of the transmission assembly being coupled to the
only one switch member and the reduction gearset assembly, the at
least one member of the transmission assembly being movable in
response to movement of the only one switch member to cause the
reduction gearset assembly to operate in one of the overall speed
reduction ratios that corresponds to an associated one of the
positions in which the only one switch member is disposed; wherein
at least two of the planetary transmission stages are operable in
the active mode for performing a speed reduction and torque
multiplication operation and in at least one of the at least three
overall speed reduction ratios.
25. The portable power tool of claim 24, wherein the input stage is
common between each of the at least three overall speed reduction
ratios.
26. The portable power tool of claim 25, wherein the at least one
intermediate stage is common between each of the at least three
overall speed reduction ratios.
27. The portable power tool of claim 24, wherein the output stage
is common between each of the at least three overall speed
reduction ratios.
28. The portable power tool of claim 27, wherein the at least one
intermediate stage is common between each of the at least three
overall speed reduction ratios.
29. The portable power tool of claim 28, wherein the input stage is
common between each of the at least three overall speed reduction
ratios.
Description
BACKGROUND OF THE DISCLOSURE
1. Technical Field
The present disclosure relates generally to power tools such as
rotatable drills, power screwdrivers, and rotatable cutting
devices. More particularly, the present disclosure relates to a
transmission for a multi-speed transmission for a power tool.
2. Discussion
Modernly, manufacturers of power tools have introduced power tools
that have variable speed motors in an attempt to permit the users
of these tools with sufficient control over the output speed of the
tool so as to permit them to perform diverse operations without
resort to additional, specialized tools. Many of the tools that are
commercially available include a three-stage, two-speed
transmission that permits even greater control over speeds of these
tools.
Typically available transmission arrangements have lacked a
transmission arrangement that could produce a wide range of output
speeds and torques that would permit the tool to perform diverse
operations such as drilling holes with a large diameter hole saw,
installing drywall screws or large diameter lag screws, and
performing high-speed drilling operations. The single or dual speed
transmissions that were generally employed in these tools typically
did not have sufficient speed reducing capacity to permit these
transmissions to be diversely employed as configuring these tools
for high torque operations tended to impair their high speed
performance. Furthermore, the rechargeable batteries that were
employed in many of the early cordless rotary power tools were not
well suited for use in low-speed, high torque operations due to the
amount of energy that is consumed and the rate with which the
energy is consumed by the power tool during such operations.
Consequently, consumers were often forced to purchase two different
rotary power tools, a medium-duty tool for "standard" applications
such as drilling and fastening, and a heavy-duty tool having a
low-speed, high torque output for more demanding tasks.
With the advent of the modern high capacity, high voltage battery,
it is now possible to meet the energy demands of a power tool that
is used in low-speed, high torque operations. There remains,
however, a need in the art for a power tool transmission having a
relatively large range in its speed reducing capacity.
SUMMARY OF THE DISCLOSURE
In one form, the present disclosure provides a portable power tool
that includes a housing, a motor, a trigger, a driven member and a
transmission. The housing can have a first portion, which can
define a handle for carrying the portable power tool, and a second
portion. The motor can be received in the second portion of the
housing and can include a motor output member. The trigger can be
coupled to the housing and can be movable to activate the motor.
The transmission can be coupled to the housing. The transmission
can be configured to receive a rotary input from the motor output
member and to produce a rotary output that is transmitted to the
driven member. The transmission can have a plurality of planetary
transmission stages. The planetary transmission stages can include
a ring gear and a set of planet gears that are meshingly engaged
with the ring gear. At least one member of the transmission may be
configured in a first condition, which renders at least one of the
planetary transmission stages operable in an active mode, and a
second condition, which renders at least one of the planetary
transmission stages operable in an inactive mode. The transmission
is operable in at least three overall speed reduction ratios and at
least three planetary transmission stages transmit torque in
sequence between the motor output member and the driven member in
each overall speed reduction ratio. The ring gear associated with
each of the at least three planetary transmission stages is not
meshingly engaged to the set of planet gears of another of the at
least three planetary transmission stages.
In another form, the present teachings provide a portable power
tool having a housing, a motor, a driven member and a transmission
assembly. The housing has a first portion, which defines a handle
for carrying the portable tool, and a second portion. The motor can
be coupled to the second portion of the housing and can include a
motor output member. The transmission assembly can be coupled to
the housing and can be configured to receive a rotary input from
the motor output member and produce a rotary output that is
transmitted to the driven member. The transmission assembly can
have a reduction gearset assembly that includes a plurality of ring
gears, a plurality of planet carriers and a plurality of sets of
planet gears. A first one of the sets of planet gears can be
supported by a first one of the planet carriers and can be
meshingly engaged with a first one of the ring gears. A second one
of the sets of planet gears can be supported by a second one of the
planet carriers and can be meshingly engaged with a second one of
the ring gears. The driven member can be coupled for rotation with
the second one of the planet carriers. At least one member of the
transmission assembly may be configured in a first condition, which
renders at least one of the planetary transmission stages operable
in an active mode, and a second condition, which renders at least
one of the planetary transmission stages operable in a mode other
than the active mode. The transmission is operable in at least
three overall speed reduction ratios. At least three planetary
transmission stages transmit torque between the motor output member
and the driven member in each overall speed reduction ratio. Each
overall speed reduction ratio includes an input stage, an output
stage and at least one intermediate stage between the input stage
and the output stage. The input stage receives the rotary input,
the output stage outputting the rotary output, the at least one
intermediate stage drivingly connecting the input stage and the
output stage. The ring gear associated with each of the at least
three planetary transmission stages is not meshingly engaged to the
planet gears of another of the at least three planetary
transmission stages.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional advantages and features of the present disclosure will
become apparent from the subsequent description and the appended
claims, taken in conjunction with the accompanying drawings,
wherein:
FIG. 1 is a side view of a power tool constructed in accordance
with the teaching of the present disclosure;
FIG. 2 is an exploded perspective view of a portion of the power
tool of FIG. 1;
FIG. 3 is a perspective view of a portion of the housing of the
power tool of FIG. 1 illustrating the rear of the end cap
assembly;
FIG. 4 is a front view of the end cap assembly;
FIG. 5 is a section view taken along the line 5-5 of FIG. 4;
FIG. 6 is a rear view of a portion of the power tool of FIG. 1 with
the end cap assembly removed;
FIG. 7 is a side view of a portion of the power tool of FIG. 1 with
the end cap assembly removed;
FIG. 8 is a view similar to that of FIG. 4, but illustrating the
end cap shell prior to the overmolding operation;
FIG. 9 is a view similar to that of FIG. 5, but illustrating the
end cap shell prior to the overmolding operation;
FIG. 10 is a view similar to that of FIG. 4, but illustrating an
alternate construction of the overmold member;
FIG. 11 is a partial sectional view of a portion of a power tool
that employs an end cap assembly having an overmold member
constructed in the manner illustrated in FIG. 10;
FIG. 12 is an exploded perspective view of a portion of the power
tool of FIG. 1, illustrating the transmission assembly in greater
detail;
FIG. 13 is an exploded perspective view of a portion of the power
tool of FIG. 1, illustrating the reduction gearset assembly, the
transmission sleeve, a portion of the housing and a portion of the
clutch mechanism in greater detail;
FIG. 13a is a sectional view taken along a longitudinal axis of the
second ring gear;
FIG. 13b is a sectional view taken along a longitudinal axis of the
third ring gear;
FIG. 14 is a side view of the transmission sleeve;
FIG. 15 is a rear view of the transmission sleeve;
FIG. 16 is a sectional view taken along the line 16-16 of FIG.
15;
FIG. 17 is a sectional view taken along the line 17-17 of FIG.
15;
FIG. 18 is an exploded view of the reduction gearset assembly;
FIG. 19 is a sectional view taken along a longitudinal axis of the
power tool of FIG. 1 illustrating a portion of the reduction
gearset assembly in greater detail;
FIG. 20 is a front view of a portion of the first reduction
carrier;
FIG. 21 is a sectional view taken along a longitudinal axis of the
power tool of FIG. 1 illustrating a portion of the reduction
gearset assembly in greater detail;
FIG. 22 is a rear view of a portion of the third reduction
carrier;
FIG. 23 is an sectional view taken along the longitudinal axis of
the power tool of FIG. 1 and illustrating the transmission assembly
as positioned in the first speed ratio;
FIG. 24 is a sectional view similar to that of FIG. 23 but
illustrating the transmission assembly as positioned in the second
speed ratio;
FIG. 25 is a sectional view similar to that of FIG. 23 but
illustrating the transmission assembly as positioned in the third
speed ratio;
FIG. 26 is a top view of a portion of the power tool of FIG. 1
illustrating the speed selector mechanism in greater detail;
FIG. 27a is a side view of the rotary selector cam;
FIG. 27b is a top view of the rotary selector cam;
FIG. 27c is a sectional view taken through along the central axis
of the speed selector mechanism;
FIG. 28 is a rear view of the output spindle assembly;
FIG. 29 is an exploded perspective view of the clutch
mechanism;
FIG. 29a is a perspective view of a portion of the clutch mechanism
illustrating another configuration of the clutch member;
FIG. 29b is an exploded perspective view illustrating a multi-piece
construction for the first ring gear and clutch member;
FIG. 30 is a schematic illustration of the adjustment structure in
an "unwrapped" state;
FIG. 31 is a schematic illustration similar to that of FIG. 30 but
showing an alternate construction of the adjustment profile;
and
FIG. 32 is a schematic illustration similar to that of FIG. 30 but
showing a portion of another alternate construction of the
adjustment profile;
FIGS. 33 through 35 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of a second
transmission constructed in accordance with the teachings of the
present disclosure;
FIGS. 36 through 38 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of a third
transmission constructed in accordance with the teachings of the
present disclosure;
FIGS. 39 through 41 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of a fourth
transmission constructed in accordance with the teachings of the
present disclosure;
FIGS. 42 through 44 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of a fifth
transmission constructed in accordance with the teachings of the
present disclosure;
FIGS. 45 through 47 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of a sixth
transmission constructed in accordance with the teachings of the
present disclosure;
FIGS. 48 through 50 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of a seventh
transmission constructed in accordance with the teachings of the
present disclosure;
FIGS. 51 through 53 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of an eighth
transmission constructed in accordance with the teachings of the
present disclosure; and
FIGS. 54 through 56 are sectional views similar to FIGS. 23 through
25, respectively, taken along the longitudinal axis of a ninth
transmission constructed in accordance with the teachings of the
present disclosure.
DETAILED DESCRIPTION
Overview
With reference to FIGS. 1 and 2 of the drawings, a power tool
constructed in accordance with the teachings of the present
disclosure is generally indicated by reference numeral 10. As those
skilled in the art will appreciate, the preferred embodiment of the
present disclosure may be either a cord or cordless (battery
operated) device, such as a portable screwdriver or drill (e.g.,
drill, hammer drill). In the particular embodiment illustrated,
power tool 10 may be a cordless drill having a housing 12, a motor
assembly 14, a multi-speed transmission assembly 16, a clutch
mechanism 18, an output spindle assembly 20, a chuck 22, a trigger
assembly 24 and a battery pack 26. Those skilled in the art will
understand that several of the components of power tool 10, such as
the chuck 22, the trigger assembly 24 and the battery pack 26, can
be conventional in nature and need not be described in significant
detail in this application. Reference may be made to a variety of
publications for a more complete understanding of the operation of
the conventional features of power tool 10. One example of such
publications is commonly assigned U.S. Pat. No. 5,897,454 issued
Apr. 27, 1999, the disclosure of which is hereby incorporated by
reference as if fully set forth herein.
Housing 12 can include an end cap assembly 30 and a handle shell
assembly 32 that can include a pair of mating handle shells 34.
Handle shell assembly 32 can include a handle portion 36 and a
drive train or body portion 38. Trigger assembly 24 and battery
pack 26 can be mechanically coupled to handle portion 36 and can be
electrically coupled to motor assembly 14. Body portion 38 can
include a motor cavity 40 and a transmission cavity 42. Motor
assembly 14 may be housed in motor cavity 40 and can include a
rotatable output shaft 44, which can extend into transmission
cavity 42. A motor pinion 46 having a plurality of gear teeth 48
may be coupled for rotation with output shaft 44. Trigger assembly
24 and battery pack 26 cooperate to selectively provide electric
power to motor assembly 14 in a manner that is generally well known
in the art so as to control the speed and direction with which
output shaft 44 rotates.
Transmission assembly 16 may be housed in transmission cavity 42
and can include a speed selector mechanism 60. Motor pinion 46 can
couple transmission assembly 16 to output shaft 44, transmitting a
relatively high speed, low torque drive input to transmission
assembly 16. Transmission assembly 16 can include a plurality of
reduction elements that can be selectively engaged by speed
selector mechanism 60 to provide a plurality of speed ratios. Each
of the speed ratios can multiply the speed and torque of the drive
input in a predetermined manner, permitting the output speed and
torque of the transmission assembly 16 to be varied in a desired
manner between a relatively low speed, high torque output and a
relatively high speed, low torque output. The transmission output
may be transmitted to the output spindle assembly 20, to which the
chuck 22 may be coupled for rotation, to permit torque to be
transmitted to a tool bit (not shown). The clutch mechanism 18 may
be coupled to transmission assembly 16 and may be operable for
limiting the magnitude of the torque associated with the drive
input to a predetermined, selectable torque limit.
Functional Overmold
With specific reference to FIGS. 2 through 9, end cap assembly 30
may include an end cap shell 100 and an overmold member 102. In the
example provided, the end cap shell 100 may be injection molded
from a plastic material, such as ABS. The end cap shell 100 defines
an end cap cavity 104 that may be sized to receive the portion of
the motor assembly 14 that extends rearwardly of the handle shell
assembly 32. A plurality of first and second radial tab apertures
108 and 110 and the abutting face 128 can be formed into the
forward face 114 of the end cap shell 100 and a plurality of screw
bosses 116 can be formed into the perimeter of the end cap shell
100. Each of the first and second radial tab apertures 108 and 110
may be sized to receive one of the first radial tabs 120 and second
radial tabs 122, respectively, that can be formed into the rearward
face 124 of the handle shells 34. The first and second radial tab
apertures 108 and 110 can cooperate with the first and second
radial tabs 122 to align the end cap shell 100 to the handle shell
assembly 32, as well as to inhibit relative rotation therebetween.
An arcuate portion 128 of the forward face 114 of the end cap shell
100 may be angled to match the abutting face 132 of the rearward
face 124 of the handle shells 34. The screw bosses 116 can be
employed to fixedly couple the end cap shell 100 to the motor cover
136 via a plurality of screws 138. The geometry of the motor cover
136 may be such that it is constrained to the handle shells 34. As
such, fastening of the end cap shell 100 to the motor cover 136 can
fixedly retain the end cap shell 100 against the rearward face 124
of the handle shell assembly 32, as well as to close off the rear
handle aperture 139 in the handle shell assembly 32.
A plurality of side apertures 140 can be formed into the sides of
the end cap shell 100 to permit air to flow through the handle
shell assembly 32 and cool the motor assembly 14 in a manner that
is well known in the art. A plurality of rear apertures 144 can be
formed into the rear of the end cap shell 100, with each of the
rear apertures 144 including a recessed portion 146, which can
extend partially into the outer surface 148 of the end cap shell
100, and a through-portion 150 that can extend completely through
the end cap shell 100. A pair of retaining tabs 152 can be formed
to extend from the interior surface 154 of the end cap shell 100
inwardly into the end cap cavity 104. A channel 156 may be formed
into the interior surface 154 of the end cap shell 100 and can
intersect each of the rear apertures 144 and the retaining tabs
152.
The overmold member 102 may be formed from a resilient material,
such as thermoplastic elastomer (e.g., HYTREL.RTM. manufactured by
E.I. du Pont de Nemours and Company) and may be simultaneously
formed and coupled to the end cap shell 100 in an injection molding
operation. In the particular example provided, the overmold member
102 can include a plurality of bumper members 170, a pair of
isolators 172 and a linking member 174. Each of the bumper members
170 can extend from a point roughly coincident with the interior
surface 154 of the end cap shell 100 to a point rearwardly of the
outer surface 148 of the end cap shell 100 by about 0.5 mm to about
1.5 mm and preferably about 0.75 mm. Construction in this manner
permits the bumper members 170 to provide a degree of shock
absorption which reduces the likelihood of damaging the end cap
shell 100 in the event that the tool 10 is dropped. Furthermore, it
is sometimes necessary for an operator to apply a relatively high
force to the tool 10, as when employing a hole saw to drill large
diameter holes. In such situations, the operator is inclined to
press onto the rear of the tool 10 to apply a force that is in-line
with the axis of the chuck 22. In such situations, the bumper
members 170 provide the operator with a relatively soft and
comfortable surface which tends to resist slipping as well as
attenuate the vibrations that can be transmitted to the
operator.
The isolators 172 can be formed about the retaining tabs 152 on the
interior surface 154 of the end cap shell 100. In the example
provided, each of the isolators 172 can include an annular member
180 that extends forwardly of the interior surface 154 of the end
cap shell 100. Construction in this manner permits the end cap
shell 100 to engage the isolators 172 to the outer diameter 14a and
the rear surface 14b of the motor housing 14c to fixedly retain the
motor 14d within the motor cover 136. This can prevent the
components of the motor assembly 14 from moving along the
longitudinal axis of the tool 10, as well as dampen vibrations that
can be created during the operation of the motor assembly 14. The
linking member 174 may be fixedly coupled to each of the bumper
members 170 and the isolators 172. The linking member 174 can
provide a flow path through which the resilient material flows
during the formation of the bumper members 170 and the isolators
172. The linking member 174 can also interconnect the bumper
members 170 and the isolators 172, thereby rendering their removal
from the end cap shell 100 more difficult.
Those skilled in the art will appreciate that this aspect of the
present disclosure may be incorporated into various other positions
within the handle assembly 32 for sealing between two or more
components, dampening vibrations or positioning one component
relative to another. One such example is illustrated in FIGS. 10
and 11 where the isolators 172 can be modified to extend around the
perimeter of a portion of the end cap cavity 104 and sealingly
contact the rear surface 14b of the motor 14d. The isolators 172
seal the interface between the end cap shell 100 and the motor
assembly 14, while the bumper members 170 seal the rear apertures
144 in the end cap shell 100. The space 188 defined by the
isolators 172 can be filled with grease or another suitable
lubricant, which lubricates a motor armature bearing 190.
Transmission Assembly
With reference to FIG. 12, the transmission assembly 16 may be a
three-stage, three-speed transmission that may include a
transmission sleeve 200, a reduction gearset assembly 202 and the
speed selector mechanism 60. With additional reference to FIGS. 13
through 17, the transmission sleeve 200 may include a wall member
210 that can define a generally transmission bore or hollow cavity
212 into which the reduction gearset assembly 202 may be disposed.
The transmission sleeve 200 can include a body 214 and a base 216.
The body 214 of the transmission sleeve 200 may be fairly uniform
in diameter and can be generally smaller in diameter than the base
216. The inside diameter of the base 216 may be sized to receive
the cylindrical nose portion 220 of the motor cover 136.
A plurality of raised lands 226 can be formed into the base 216.
The raised lands 226 can define a plurality of first grooves 228 in
the outer surface 230 of the base 216 and a plurality of second
grooves 232 in the inner surface 234 of the base 216. The first
grooves 228 can be configured to receive the alignment ribs 238
that can be formed into the inner surface 242 of the handle shells
34 to align the transmission sleeve 200 to the handle shells 34 and
inhibit relative rotation between the transmission sleeve 200 and
the housing 12. The first grooves 228 and alignment ribs 238 can be
configured in a manner that the transmission sleeve 200 can only be
assembled to the handle shells 34 in one orientation (i.e., the
configuration of the first grooves 228 and alignment ribs 238
prevents the transmission sleeve 200 from being rotated 180.degree.
out of position relative to the handle shells 34). The second
grooves 232 will be discussed in greater detail, below.
The body 214 of the transmission sleeve 200 may include a
cylindrical body portion 246 and a pin housing portion 248. In the
particular embodiment illustrated, the cylindrical body portion 246
can include a selector cam guide 250, a plurality of lubricant
grooves 252 and first and second sets of ring engagement teeth 254
and 256, respectively. The selector cam guide 250 may be generally
rectangular in cross section, extending outwardly from the top of
the outer surface 258 of the body portion 246. The lubricant
grooves 252 can be formed concentrically around the upper half of
the perimeter of the body portion 246. The lubricant grooves 252
have a depth of about 0.01 inch to about 0.030 inch to hold a
lubricant, such as grease, on the upper half of the perimeter of
the body portion 246. The operation of the selector cam guide 250
and the lubricant grooves 252 will be discussed in detail,
below.
A raised bead 264 can segregate the interior of the body portion
246 into first and second housing portions 260 and 262,
respectively. The first set of ring engagement teeth 254 can be
formed onto the inner surface 266 of the body portion 246 and can
extend rearwardly from the raised bead 264 toward the base 216. The
second set of ring engagement teeth 256 can be also formed into the
inner surface of the body portion 246 and can extend forwardly from
the raised bead 264. The teeth 268 of the first and second sets of
ring engagement teeth 254 and 256 can be uniformly spaced around
the inner surface 266 of the body portion 246. The configuration of
each tooth 268 in the first and second sets of ring engagement
teeth 254 and 256 can be similar in that each tooth can extend from
the raised bead 264, can have a pair of parallel engagement
surfaces 270 and can terminate at a tip portion 272. The tip
portion 272 of each tooth 268 may be both rounded and tapered to
enhance the ability with which it will mesh with a portion of the
reduction gearset assembly 202 as will be described in detail,
below.
The pin housing portion 248 can extend downwardly from the body
portion 246 over a portion of the length of the body portion 246.
An actuator aperture 274 may be formed into the pin housing portion
248 and can extend rearwardly through the base 216 of the
transmission sleeve 200. In the particular embodiment illustrated,
the actuator aperture 274 may be stepped, having a first portion
276 with a first diameter at the rear of the transmission sleeve
200 and a second portion 278 with a smaller second diameter at the
front of the transmission sleeve 200. In the example shown, the
first portion 276 of the actuator aperture 274 breaks through the
wall of the first housing portion 260 and forms a groove 280 into
the inner surface 234 of the base 216. The pin housing portion 248
will be discussed in further detail, below.
A pair of first clip slots 284 and a pair of second clip slots 286
can be formed into the transmission sleeve 200, extending along the
sides of the transmission sleeve 200 in a manner that may be
parallel the longitudinal axis of the transmission sleeve 200. The
first pair of clip slots 284 may be formed through the sides of the
body portion 246 rearwardly of the raised bead 264 and extends
rearwardly toward the base 216. The depth of the first pair of clip
slots 284 may be such that they do not extend through the portion
of the wall member 210 that defines the base 216. The second pair
of clip slots 286 can be also formed through the sides of the body
portion 246 beginning forwardly of the raised bead 264 and
extending through the front face 288 of the transmission sleeve
200.
With reference to FIGS. 12, 13, 18 and 23, the reduction gearset
assembly 202 may include a first reduction gear set 302, a second
reduction gear set 304 and a third reduction gear set 306. The
first, second and third reduction gear sets 302, 304 and 306 can be
operable in an active mode and in the particular example provided,
the second and third reduction gear sets 304 and 306 may also be
operable in an inactive mode. Operation in the active mode causes
the reduction gear set to perform a speed reduction and torque
multiplication operation, while operation of the reduction gear set
in an inactive mode for causes the reduction gear set to provide an
output having a speed and torque that may be about equal to the
speed and torque of the rotary input provided to that reduction
gear set. In the particular embodiment illustrated, each of the
first, second and third reduction gear sets 302, 304 and 306 can be
planetary gear sets. Those skilled in the art will understand,
however, that various other types of reduction gear sets that can
be well known in the art may be substituted for one or more of the
reduction gear sets forming the reduction gearset assembly 202.
As shown, the first reduction gear set 302 may include a first
reduction element or ring gear 310, a first set of planet gears 312
and a first planet or reduction carrier 314. The first ring gear
310 may be an annular structure, having a plurality of gear teeth
310a formed along its interior diameter. A clutch face 316 may be
formed into the outer perimeter of the front face 318 of the first
ring gear 310 and will be discussed in greater detail, below. The
first ring gear 310 may be disposed within the portion of the
hollow cavity 212 defined by the base 216; the front face 318 of
the first ring gear 310 contacts a step 320 formed into the
transmission sleeve 200, thereby limiting the ability of the first
ring gear 310 to move forwardly into the hollow cavity 212.
The first reduction carrier 314 may be formed in the shape of a
flat cylinder, having plurality of pins 322 that extend from its
rearward face 324. A plurality of gear teeth 314a can be formed
into almost the entire outer perimeter of the first reduction
carrier 314, with a valley 314b being formed between each pair of
adjacent gear teeth 314a. Due to the spacing of the gear teeth
314a, one of the valleys (i.e., valley 314b') is relatively larger
than the remaining valleys 314b due to the omission of a tooth 314a
in the outer perimeter of the first reduction carrier 314. In the
particular embodiment illustrated, the gear teeth 314a of the first
reduction carrier 314 can be configured so as not to be meshingly
engagable with the gear teeth 310a of the first ring gear 310.
With specific reference to FIGS. 19 and 20, the profile of the gear
teeth 314a is illustrated in greater detail. As shown, each gear
tooth 314a terminates at a gradual radius 326 at the forward face
328 of the first reduction carrier 314 but terminates abruptly at
the rearward face 324 of the first reduction carrier 314. A radius
330 is also formed on the valleys 314b between the gear teeth
314a.
Returning to FIGS. 12, 13, 15, 18 and 23, a first thrust washer 332
having a first annular portion 334, a second annular portion 336
and a plurality of retaining tabs 338 may be positioned rearwardly
of the first reduction gear set 302. The retaining tabs 338 engage
the second grooves 232 in the base 216 of the transmission sleeve
200 and as such, relative rotation between the first thrust washer
332 and the transmission sleeve 200 may be inhibited. The inside
diameter of the base 216 may be sized to receive the motor cover
136 and as such, the front face 340 of the motor cover 136 inhibits
the axial movement of the first thrust washer 332. The first
annular portion 334 contacts the rear face 342 of the first ring
gear 310, providing a wear surface and controlling the amount by
which the first ring gear 310 is able to move in an axial
direction. The second annular portion 336 may be spaced axially
apart from the first annular portion 334, extending forwardly of
the first annular portion 334 to provide a wear surface for the
first set of planet gears 312 that also controls the amount by
which they can move in an axial direction.
The first set of planet gears 312 may include a plurality of planet
gears 344, each of which being generally cylindrical in shape,
having a plurality of gear teeth 344a formed into its outer
perimeter and a pin aperture 346 formed its their center. Each
planet gear 344 may be rotatably supported on an associated one of
the pins 322 and the first reduction carrier 314 and may be
positioned such that its teeth 344a meshingly engage the teeth 314a
of the first ring gear 310. A raised portion 348 may be formed into
the front and rear face 350 and 352 of each planet gear 344 that
inhibits the teeth 344a from rubbing on the first reduction carrier
314 and the first thrust washer 332 and creating dust or chips that
would impair the performance of the transmission assembly 16 and
reduce its operating life. As the teeth 46a of the motor pinion 46
on the output shaft 44 can be also meshingly engaged with the teeth
344a of the planet gears 344, the motor pinion 46 serves as a sun
gear for the first reduction gear set 302.
The second reduction gear set 304 may be disposed within the
portion of the hollow cavity 212 defined by the first housing
portion 260 and may include a second sun gear 358, a second
reduction element or ring gear 360, a second set of planet gears
362 and a second planet or reduction carrier 364. The second sun
gear 358 may be fixed for rotation with the first reduction carrier
314. The second sun gear 358 can include a plurality of gear teeth
358a that extend forwardly of the forward face 328 of the first
reduction carrier 314.
The second ring gear 360 may be an annular structure, having a
plurality of gear teeth 360a formed along its interior diameter.
The gear teeth 360a may be heavily chamfered at the rear face 366
of the second ring gear 360 but terminate abruptly at the front
face 368. More preferably, a heavy radius 369 may be formed onto
the rear face 366 and the sides of each of the gear teeth 360a,
with the heavy radius 369 being employed rather than the heavy
chamfer as the heavy radius 369 on the gear teeth 360a provides for
better engagement between the second ring gear 360 and the first
reduction carrier 314.
A plurality of sleeve engagement teeth 370 can be formed into the
outer perimeter of the second ring gear 360; the sleeve engagement
teeth 370 extend forwardly toward the front face 368 of the second
ring gear 360 and terminate at a tip portion 372 that may be
rounded and tapers forwardly and inwardly. An annular clip groove
374 may also formed into the outer perimeter of the second ring
gear 360. In the example illustrated, the clip groove 374 may be a
rectangular slot having a pair of sidewalls 376. The clip groove
374 will be discussed in greater detail, below.
The second reduction carrier 364 may be formed in the shape of a
flat cylinder, having plurality of pins 378 that extend from its
rearward face 380. The second set of planet gears 362 may include a
plurality of planet gears 382. Each planet gear 382 may be
generally cylindrical in shape, having a plurality of gear teeth
382a formed into its outer perimeter and a pin aperture 384 formed
its center. Each planet gear 382 may be rotatably supported on an
associated one of the pins 378 and the second reduction carrier 364
may be positioned such that the gear teeth 382a of the planet gears
382 meshingly engage the gear teeth 360a of the second ring gear
360. The gear teeth 358a of the second sun gear 358 can be also
meshingly engaged with the gear teeth 382a of the planet gears
382.
The third reduction gear set 306 may be disposed within the portion
of the hollow cavity 212 defined by the second housing portion 262
and may include a third sun gear 398, a third reduction element or
ring gear 400, a third set of planet gears 402 and a third planet
or reduction carrier 404. The third sun gear 398 may be fixed for
rotation with the second reduction carrier 364. The third sun gear
398 can include a plurality of gear teeth 398a that extend
forwardly of the front face 406 of the second reduction carrier
364.
The third ring gear 400 may be an annular structure, having a
plurality of gear teeth 400a formed along its interior diameter.
The gear teeth 400a may be heavily chamfered at the front face 412
of the third ring gear 400, but terminate abruptly at the rear face
414. More preferably, a heavy radius 407 may be formed onto the
front face 412 and the sides of each of the gear teeth 400a, with
the heavy radius 407 being employed rather than the heavy chamfer
as the heavy radius 407 on the gear teeth 400a provides for better
engagement between the third ring gear 400 and the third reduction
carrier 404. A plurality of sleeve engagement teeth 418 can be
formed into the outer perimeter of the third ring gear 400; the
sleeve engagement teeth 418 extend rearward toward the rear face
414 of the third ring gear 400 and terminate at a tip portion 420
that may be rounded and taper both rearwardly and inwardly. An
annular clip groove 422 may also be formed into the outer perimeter
of the third ring gear 400. In the example illustrated, the clip
groove 422 may be a rectangular slot having a pair of sidewalls
424. The clip groove 422 will be discussed in greater detail,
below.
The third reduction carrier 404 may be formed in the shape of a
flat cylinder, having plurality of pins 428 that extend from its
rearward face 430. A plurality of gear teeth 404a can be formed
into almost the entire outer perimeter of the third reduction
carrier 404, with a valley 404b being formed between each pair of
adjacent teeth 404a. Due to the spacing of the teeth 404a, one of
the valleys 404b (i.e., valley 404b') is relatively larger than the
remaining valleys 404b due to the omission of a tooth 404a in the
outer perimeter of the third reduction carrier 404. In the
particular embodiment illustrated, the gear teeth 404a of the third
reduction carrier 404 can be configured so as not to be meshingly
engagable with the gear teeth 382a of the second planet gears
382.
With brief additional reference to FIGS. 21 and 22, the profile of
the gear teeth 404a is illustrated in greater detail. As shown, the
rear face 430 of the third reduction carrier 404 may be chamfered
and a heavy radius 434 may be formed into each of sides of the
teeth 404a and valleys 404b. Each gear tooth 404a terminates
abruptly at the forward face 436 of the third reduction carrier
404.
Returning back to FIGS. 12, 13, 15, 18 and 23, the third set of
planet gears 402 may include a plurality of planet gears 438. Each
planet gear 438 may be generally cylindrical in shape, having a
plurality of gear teeth 438a formed into its outer perimeter and a
pin aperture 440 formed through its center. Each planet gear 438
may be rotatably supported on an associated one of the pins 428 and
the third reduction carrier 404 may be positioned such that the
gear teeth 438a of the planet gears 438 meshingly engage the gear
teeth 400a of the third ring gear 400. A raised portion 442 may be
formed into each of the front and rear faces of the planet gears
438 which inhibits the gear teeth 438a from rubbing on the third
reduction carrier 404 and creating dust or chips that would impair
the performance of the transmission assembly 12 and reduce its
operating life. A second thrust washer 450 may be disposed around
the third sun gear 398 and the teeth 398a of the third sun gear 398
can be meshingly engaged with the gear teeth 438a of the planet
gears 438. The second thrust washer 450 may include a plurality of
retaining tabs 452 that can be configured to engage corresponding
tab grooves 454 (FIG. 13) that can be formed in the inner surface
266 of body portion 246 of the transmission sleeve 200. The
retaining tabs 452 and the tab grooves 454 cooperate to inhibit
relative rotation between the second thrust washer 450 and the
transmission sleeve 200.
The output spindle assembly 20 may include a transmitting means 458
for coupling a spindle 460 for rotation with the third reduction
carrier 404 so as to transmit drive torque from the reduction
gearset assembly 202 to the chuck 22. Such transmitting means 458
are well known in the art and easily adapted to the transmission
assembly of the present disclosure. Accordingly, a detailed
discussion of the transmitting means 458 need not be included
herein.
With reference to FIGS. 13, 13a, 13b, 16, 17, 18 and 23 through 28,
the speed selector mechanism 60 may be movable between a first
position 500, a second position 502 and a third position 504 and
can include a switch portion 510 for receiving a speed change input
and an actuator portion 512 for manipulating the reduction gearset
assembly 202 in accordance with the speed change input. The
actuator portion 512 may be operatively coupled to the reduction
gearset assembly 202 and moves the second and third reduction gear
sets 304 and 306 between the active and inactive modes in response
to movement of the switch portion 510 between the first, second and
third positions 500, 502 and 504. In the particular embodiment
illustrated, the actuator portion 512 can include a rotary selector
cam 520, a plurality of wire clips 522 and a spring member 523.
Each of the wire clips 522 may be formed from a round wire which
may be bent in the shape of a semi-circle 524 with a pair of tabs
526 extending outwardly from the semi-circle 524 and positioned on
about the centerline of the semi-circle 524. The semi-circle 524
may be sized to fit within the clip grooves 374 and 422 in the
second and third ring gears 360 and 400, respectively. In this
regard, the semi-circle 524 neither extends radially outwardly of
an associated one of the ring gears (360, 400), nor binds against
the sidewalls (376, 424) of the clip grooves (374, 422). In the
example provided, the sidewalls (376, 424) of the clip grooves
(374, 422) are spaced apart about 0.05 inch and the diameter of the
wire forming the wire clips 522 may be about 0.04 inch.
The tabs 526 of the wire clips 522 extend outwardly of the hollow
cavity 212 into an associated one of the clip slots (284, 286) that
may be formed into the transmission sleeve 200. The tabs 526 can be
long enough so that they extend outwardly of the outer surface 258
of the body 214 of the transmission sleeve 200, but not so far as
to extend radially outwardly of the portion of the first clip slots
284 in the base 216 of the transmission sleeve 200. Configuration
of the wire clips 522 in this manner facilitates the assembly of
the transmission assembly 16, permitting the wire clips 522 to be
installed to the second and third ring gears 360 and 400, after
which these assemblies can be inserted into the hollow cavity 212
along the longitudinal axis of the transmission sleeve 200.
With specific reference to FIGS. 13 and 27a through 27c, the rotary
selector cam 520 may include an arcuate selector body 530, a switch
tab 532 and a plurality of spacing members 534. A pair of first cam
slots 540a and 540b, a pair of second cam slots 544a and 544b, a
spring aperture 546 and a guide aperture 548 can be formed through
the selector body 530. The selector body 530 may be sized to engage
the outside diameter of the body portion 246 of the transmission
sleeve 200 in a slip-fit manner. The guide aperture 548 may be
generally rectangular in shape and sized to engage the front and
rear surfaces of the selector cam guide 250. The guide aperture 548
may be considerably wider than the width of the selector cam guide
250, being sized in this manner to permit the rotary selector cam
520 to be rotated on the transmission sleeve 200 between a first
rotational position, a second rotational position and a third
rotational position. The selector cam guide 250 and cooperates with
the guide aperture 548 to limit the amount by which the rotary
selector cam 520 can be rotated on the transmission sleeve 200,
with a first lateral side of the selector cam guide 250 contacting
a first lateral side of the guide aperture 548 when the rotary
selector cam 520 is positioned in the first rotational position,
and a second lateral side of the selector cam guide 250 contacting
a second lateral side of the guide aperture 548 when the rotary
selector cam 520 is positioned in the third rotational
position.
Each of the first cam slots 540a and 540b may be sized to receive
one of the tabs 526 of the wire clip 522 that is engaged to the
second ring gear 360. In the particular embodiment illustrated,
first cam slot 540a can include a first segment 550, a second
segment 552 and an intermediate segment 554. The first segment 550
may be located a first predetermined distance away from a reference
plane 558 that may be perpendicular to the longitudinal axis of the
rotary selector cam 520 and the second segment 552 may be located a
second distance away from the reference plane 558. The intermediate
segment 554 couples the first and second segments 550 and 552 to
one another. The configuration of first cam slot 540b is identical
to that of first cam slot 540a, except that it is rotated relative
to the rotary selector cam 520 such that each of the first, second
and intermediate segments 550, 552 and 554 in the first cam slot
540b can be located 180.degree. apart from the first, second and
intermediate segments 550, 552 and 554 in the first cam slot
540a.
Each of the second cam slots 544a and 544b may be sized to receive
one of the tabs 526 of a corresponding one of the wire clips 522.
In the particular embodiment illustrated, second cam slot 544a can
include a first segment 560, a second segment 562, a third segment
564 and a pair of intermediate segments 566 and 568. The first and
third segments 560 and 564 can be located a third predetermined
distance away from the reference plane and the second segment 562
may be located a fourth distance away from the reference plane 558.
The intermediate segment 566a couples the first and second segments
560 and 562 to one another and the intermediate segment 568 couples
the second and third segments 562 and 566 together. The
configuration of second cam slot 544b is identical to that of
second cam slot 544a, except that it is rotated relative to the
rotary selector cam 520 such that each of the first, second, third
and intermediate segments 560, 562, 564 and 566 and 568 in the
second cam slot 544b can be located 180.degree. apart from the
first, second, third and intermediate segments 560, 562, 564 and
566 and 568 in the second cam slot 544a.
With the tabs 526 of the wire clips 522 engaged to the first cam
slots 540a and 540b and the second cam slots 544a and 544b, the
rotary selector cam 520 may be rotated on the transmission sleeve
200 between the first, second and third positions 500, 502 and 504
to selectively engage and disengage the second and third ring gears
360 and 400 from the first and third reduction carriers 314 and
404, respectively. During the rotation of the rotary selector cam
520, the first cam slots 540a and 540b and the second cam slots
544a and 544b confine the wire tabs 526 of their associated wire
clip 522 and cause the wire tabs 526 to travel along the
longitudinal axis of the transmission sleeve 200 in an associated
one of the first and second clip slots 284 and 286. Accordingly,
the rotary selector cam 520 may be operative for converting a
rotational input to an axial output that causes the wire clips 522
to move axially in a predetermined manner. A lubricant (not
specifically shown) may be applied to the lubricant grooves 252
formed into body portion 246 of the transmission sleeve 200 may be
employed to lubricate the interface between the transmission sleeve
200 and the rotary selector cam 520.
Positioning the rotary selector cam 520 in the first rotational
position 500 causes the tabs 526 of the wire clip 522 that is
engaged to the second ring gear 360 to be positioned in the first
segment 550 of the first cam slots 540a and 540b and the tabs 526
of the wire clip 522 that is engaged to the third ring gear 400 to
be positioned in the first segment 560 of the second cam slots 544a
and 544b. Accordingly, positioning of the rotary selector cam 520
in the first rotational position causes the second and third ring
gears 360 and 400 to be positioned in meshing engagement with the
second and third planet gears 362 and 402, respectively.
Simultaneously with the meshing engagement of the second and third
ring gears 360 and 400 with the second and third planet gears 362
and 402, the sleeve engagement teeth 370 and 418 of the second and
third ring gears 360 and 400, respectively, can be positioned in
meshing engagement with the first and second sets of ring
engagement teeth 254 and 256, respectively, to inhibit relative
rotation between the second and third ring gears 360 and 400 and
the transmission sleeve 200 to thereby providing the transmission
assembly 16 with a first overall gear reduction or speed ratio 570
as shown in FIG. 23. Those skilled in the art will understand that
the tip portion 272 of the teeth 268 of the first and second sets
of ring engagement teeth 254 and 256 and the tip portions 372 and
420 of the sleeve engagement teeth 370 and 418, respectively, can
be rounded and tapered so as to improve their capability for
meshing engagement in response to axial repositioning along a
longitudinal axis of the transmission assembly 16.
Positioning the rotary selector cam 520 in the second rotational
position 502 causes the tabs 526 of the wire clip 522 that is
engaged to the second ring gear 360 to be positioned in the first
segment 550 of the first cam slots 540a and 540b and the tabs 526
of the wire clip 522 that is engaged to the third ring gear 400 to
be positioned in the second segment 562 of the second cam slots
544a and 544b. Accordingly, positioning of the rotary selector cam
520 in second rotational position causes the second ring gear 360
to be in meshing engagement with the second planet gears 362 and
the third ring gear 400 in meshing engagement with both the third
planet gears 402 and the third reduction carrier 404. Positioning
of the rotary selector cam 520 in the second rotational position
502 also positions the sleeve engagement teeth 370 of the second
ring gear 360 in meshing engagement with the first set of ring
engagement teeth 254 while the sleeve engagement teeth 418 of the
third ring gear 400 can be not meshingly engaged with the second
set of ring engagement teeth 256. As such, relative rotation
between the second ring gear 360 and the transmission sleeve 200 is
inhibited, while relative rotation between the third ring gear 400
and the transmission sleeve 200 is permitted to thereby provide the
transmission assembly 16 with a second overall gear reduction or
speed ratio 572 as illustrated in FIG. 24.
Positioning the rotary selector cam 520 in the third rotational
position 504 causes the tabs 526 of the wire clip 522 that is
engaged to the second ring gear 360 to be positioned in the second
segment 552 of the first cam slots 540a and 540b and the tabs 526
of the wire clip 522 that is engaged to the third ring gear 400 to
be positioned in the third segment 564 of the second cam slots 544a
and 544b. Accordingly, positioning of the rotary selector cam 520
in the third rotational position causes the second ring gear 360 to
be in meshing engagement with both the second planet gears 362 and
the first reduction carrier 314 while the third ring gear 400 in
meshing engagement with only the third planet gears 402.
Positioning the rotary selector cam 520 in the third rotation
position 504 also positions the sleeve engagement teeth 370 on the
second ring gear 360 out of meshing engagement with the first set
of ring engagement teeth 254 and the sleeve engagement teeth 418 on
the third ring gear 400 in meshing engagement with the second sets
of ring engagement teeth 256 to inhibit relative rotation between
the second ring gear 360 and the transmission sleeve 200 and permit
relative rotation between the third ring gear 400 and the
transmission sleeve 200 to provide the transmission assembly 16
with a third overall gear reduction or speed ratio 574.
In the example shown in FIGS. 13, 27b and 28, the spring member 523
may be formed from a flat rectangular piece of spring steel and can
include a flattened Z-shaped portion 580 and a raised portion 584.
The flattened Z-shaped portion 580 may be configured to wrap around
two reinforcement bars 586 that extend into the spring aperture
546, thereby permitting the raised portion 584 to be maintained at
a predetermined position and also to transmit a spring force
between the rotary selector cam 520 and the spring member 523. With
additional reference to FIG. 28, the raised portion 584 of the
spring member 523 may be sized to engage internal notches 590
formed in the housing 592 of the output spindle assembly 20. Lands
594 that can be circumferentially spaced from the rotary selector
cam 520 can be formed between the notches 590. When the output
spindle assembly 20 is positioned over the transmission assembly 16
and the speed selector mechanism 60 is positioned in one of the
first, second and third rotational positions 500, 502 and 504, the
raised portion 584 of the spring member 523 engages an associated
one of the notches 590. The force that is generated by the spring
member 523 when the raised portion 584 is moved downwardly toward
the rotary selector cam 520 in response to contact between the
raised portion 584 and the land 594 acts to inhibit unintended
rotation of the speed selector mechanism 60. Furthermore, placement
of the raised portion 584 in a notch 590 provides the user with a
tactile indication of the positioning of the rotary selector cam
520.
In the particular embodiment illustrated in FIGS. 13 and 27c,
switch portion 510 may include an arcuate band 600 having a raised
hollow and rectangular selector button 602 formed therein. The
arcuate band 600 may be formed from a plastic material and may be
configured to conform to the outer diameter of the rotary selector
cam 520. The open end of the selector button 602 may be configured
to receive the switch tab 532, thereby permitting the switch
portion 510 and the rotary selector cam 520 to be coupled to one
another in a fastenerless manner. The plurality of spacing members
534 can be raised portions formed into the rotary selector cam 520
that can be concentric to and extend radially outwardly from the
selector body 530. The spacing members 534 elevate the arcuate band
600 to prevent the arcuate band from contacting the wire tabs 526
in the first cam slots 540a and 540b. The spacing members 534 may
also be employed to selectively strengthen areas of the rotary
selector cam 520, such as in the areas adjacent the first cam slots
540a and 540b.
Those skilled in the art will understand that the rotary selector
cam 520 (i.e., the first cam slots 540a and 540b and the second cam
slots 544a and 544b) could be configured somewhat differently so as
to cause the second ring gear 360 meshingly engages both the second
planet gears 362 and the first reduction carrier 314 while the
third ring gear 400 meshingly engages both the third planet gears
402 and the third reduction carrier 404 to thereby providing the
transmission assembly 16 with a fourth overall gear reduction or
speed ratio.
Those skilled in the art will also understand that selector
mechanisms of other configurations may be substituted for the
selector mechanism 60 illustrated herein. These selector mechanisms
may include actuators that can be actuated via rotary or sliding
motion and may include linkages, cams or other devices that are
well known in the art to slide the second and third ring gears 360
and 400 relative to the transmission sleeve 200. Those skilled in
the art will also understand that as the second and third ring
gears 360 and 400 can be independently movable between the active
and inactive modes (i.e., the placement of one of the second and
third ring gears 360 and 400 does not dictate the positioning of
the other one of the second and third ring gears 360 and 400), the
switch mechanism 60 could also be configured to position the second
and third ring gears 360 and 400 independently of one another.
Clutch Mechanism
In FIGS. 23, 26 and 28 through 30, the clutch mechanism 18 may
include a clutch member 700, an engagement assembly 702 and an
adjustment mechanism 704. The clutch member 700 may be an annular
structure that may be fixed to the outer diameter of the first ring
gear 310 and which extends radially outwardly therefrom. The clutch
member 700 may include a clutch face 316 that may be formed into
the front face 318 of the first ring gear 310. The outer diameter
of the clutch member 700 may be sized to rotate within the portion
of the hollow cavity 212 that is defined by the base 216 of the
transmission sleeve 200. With specific brief reference to FIG. 29,
the clutch face 316 of the example illustrated is shown to be
defined by a plurality of peaks 710 and valleys 712 that can be
arranged relative to one another to form a series of ramps that can
be defined by an angle of about 18.degree.. Those skilled in the
art will understand, however, that other clutch face configurations
may also be employed, such as a sinusoidally shaped clutch face
316' (FIG. 29a).
While the first ring gear 310 and the clutch member 700 have been
illustrated as a one piece (i.e., unitarily formed) construction,
those skilled in the art will understand that they may be
constructed otherwise. One such embodiment is illustrated in FIG.
29b wherein the first ring gear 310' may include an annular collar
1000 and a plurality of tab apertures 1002. The annular collar 1000
may include a plurality of ramps 1004 that have dual sloping sides,
but is otherwise flat. The first ring gear 310' is otherwise
identical to the first ring gear 310. An annular damper 1008 abuts
the annular collar 1000 and can include a plurality of tab members
1010 that engage the tab apertures 1002 in the first ring gear 310'
to prevent the damper 1008 from rotating relative to the first ring
gear 310'. The damper 1008 can include a body portion 1012 that may
be configured to match the contour of the annular collar 1000 and
as such, can include a plurality of mating ramped portions 1014
that can be configured to engage each of the ramps 1004. The damper
1008 may be formed from a suitable impact dampening material, such
as acetyl. The clutch member 700', which may be an annular member
that may be formed from a wear resistant material, such as hardened
8620 steel, may be disposed over the damper 1008. Like the damper
1008, the clutch member 700' can include a plurality of tab members
1020, which lock into the tab apertures 1002 to prevent rotation
relative to the first ring gear 310', and a plurality of mating
ramped portions 1022. The mating ramped portions 1022 of the clutch
member 700', however, matingly engage the mating ramped portions
1014 of the damper 1008. While the construction in this manner is
more expensive relative to the previously described embodiment, it
is more tolerant of high impact forces that can be associated with
the operation of the clutch mechanism 18.
In the particular embodiment illustrated, the engagement assembly
702 can include a pin member 720, a follower spring 722 and a
follower 724. The pin member 720 can include a cylindrical body
portion 730 having an outer diameter that may be sized to slip-fit
within the second portion 278 of the actuator aperture 274 that is
formed into the pin housing portion 248 of the transmission sleeve
200. The pin member 720 also can include a tip portion 732 and a
head portion 734. The tip portion 732 may be configured to engage
the adjustment mechanism 704 and in the example shown, is formed
into the end of the body portion 730 of the pin member 720 and
defined by a spherical radius. The head portion 734 may be coupled
to the end of the body portion 730 opposite the tip portion 732 and
may be shaped in the form of a flat cylinder or barrel that is
sized to slip fit within the first portion 276 of the actuator
aperture 274. Accordingly, the head portion 734 prevents the pin
member 720 from being urged forwardly out of the actuator aperture
274.
The follower spring 722 may be a compression spring whose outside
diameter may be sized to slip fit within the first portion 276 of
the actuator aperture 274. The forward end of the follower spring
722 contacts the head portion 734 of the pin member 720, while the
opposite end of the follower spring 722 contacts the follower 724.
The end portion 740 of the follower 724 may be cylindrical in shape
and sized to slip fit within the inside diameter of the follower
spring 722. In this regard, the end portion 740 of the follower
acts as a spring follower to prevent the follower spring 722 from
bending over when it is compressed. The follower 724 also can
include a follower portion 744 having a cylindrically shaped body
portion 746, a tip portion 748 and a flange portion 750. The body
portion 746 may be sized to slip fit within the first portion 276
of the actuator aperture 274. The tip portion 748 may be configured
to engage the clutch face 316 and in the example shown, is formed
into the end of the body portion 746 of the follower 724 and
defined by a spherical radius. The flange portion 750 may be formed
at the intersection between the body portion 746 and the end
portion 740. The flange portion 750 may be generally flat and
configured to receive a biasing force that may be exerted by the
follower spring 722.
The adjustment mechanism 704 may also include an adjustment
structure 760 and a setting collar 762. The adjustment structure
760 may be shaped in the form of a generally hollow cylinder that
may be sized to fit a housing portion 766 of the output spindle
assembly 20. The adjustment structure 760 can include an annular
face 768 into which an adjustment profile 770 may be formed. The
adjustment profile 770 can include a first adjustment segment 772,
a last adjustment segment 774, a plurality of intermediate
adjustment segments 776 and a ramp section 778 between the first
and last adjustment segments 772 and 774. In the embodiment
illustrated, a second ramp section 779 is included between the last
intermediate adjustment segment 776z and the last adjustment
segment 774. Also in the particular embodiment illustrated, the
portion of the adjustment profile 770 from the first adjustment
segment 772 through the last one of the intermediate adjustment
segments 776z is formed as a ramp having a constant slope.
Accordingly, a follower 780 that is coupled to the housing portion
766 of the output spindle assembly 20 may be biased radially
outwardly toward the inside diameter of the adjustment structure
760 where it acts against the plurality of detents 782 that can be
formed into the adjustment mechanism 704 (e.g., in the setting
collar 762). The follower 724 and plurality of detents 782
cooperate to provide the user of tool 10 with a tactile indication
of the position of the adjustment profile 770 as well as inhibit
the free rotation of the adjustment structure 760 so as to maintain
the position of the adjustment profile 770 at a desired one of the
adjustment segments 772, 774 and 776.
The setting collar 762 may be coupled to the exterior of the
adjustment structure 760 and may include a plurality of raised
gripping surfaces 790 that permit the user of the tool 10 to
comfortably rotate both the setting collar 762 and the adjustment
structure 760 to set the adjustment profile 770 at a desired one of
the adjustment segments 772, 774 and 776. A setting indicator 792
may be employed to indicate the position of the adjustment profile
770 relative to the housing portion 766 of the output spindle
assembly 20. In the example provided, the setting indicator 792 can
include an arrow 794 formed into the housing portion 766 of the
output spindle assembly 20 and a scale 796 that is marked into the
circumference of the setting collar 762.
During the operation of the tool 10, an initial drive torque is
transmitted by the motor pinion 46 from the motor assembly 14 to
the first set of planet gears 312 causing the first set of planet
gears 312 to rotate. In response to the rotation of the first set
of planet gears 312, a first intermediate torque is applied against
the first ring gear 310. Resisting this torque is a clutch torque
that is applied by the clutch mechanism 18. The clutch torque
inhibits the free rotation of the first ring gear 310, causing the
first intermediate torque to be applied to the first reduction
carrier 314 and the remainder of the reduction gearset assembly 202
so as to multiply the first intermediate torque in a predetermined
manner according to the setting of the switch mechanism 60. In this
regard, the clutch mechanism 18 biases the first reduction gear set
302 in the active mode.
The magnitude of the clutch torque is dictated by the adjustment
mechanism 704, and more specifically, the relative height of the
adjustment segment 772, 774 or 776 that is in contact with the tip
portion 732 of the pin member 720. Positioning of the adjustment
mechanism 704 at a predetermined one of the adjustment segments
772, 774 or 776 pushes the pin member 720 rearwardly in the
actuator aperture 274, thereby compressing the follower spring 722
and producing the a clutch force. The clutch force is transmitted
to the flange portion 750 of the follower 724, causing the tip
portion 748 of the follower 724 to engage the clutch face 316 and
generating the clutch torque. Positioning of the tip portion 748 of
the follower 724 in one of the valleys 712 in the clutch face 316
operates to inhibit rotation of the first ring gear 310 relative to
the transmission sleeve 200 when the magnitude of the clutch torque
exceeds the first intermediate torque. When the first intermediate
torque exceeds the clutch torque, however, the first ring gear 310
is permitted to rotate relative to the transmission sleeve 200.
Depending upon the configuration of the clutch face 316, rotation
of the first ring gear 310 may cause the clutch force to increase a
sufficient amount to resist further rotation. In such situations,
the first ring gear 310 will rotate in an opposite direction when
the magnitude of the first intermediate torque diminishes,
permitting the tip portion 748 of the follower 724 to align in one
of the valleys 712 in the clutch face 316. If rotation of the first
ring gear 310 does not cause the clutch force to increase
sufficiently so as to fully resist rotation of the first ring gear
310, the first reduction gearset 302 will rotate so as to limit the
transmission of torque to the first reduction carrier 314.
Configuration of the clutch mechanism 18 in this manner is highly
advantageous in that the clutch torque is sized to resist the first
intermediate torque, as opposed to the output torque of the tool 10
that is generated by the multi-reduction transmission assembly 16
and transmitted through the chuck 22. In this regard, the clutch
mechanism 18 may be sized in a relatively small manner, thereby
improving the ability with which it may be incorporated or packaged
into the tool 10. Furthermore, as the speed or gear ratios can be
changed after or down stream of the first ring gear 310, the clutch
mechanism 18 is operable over a relatively large span of output
torques. In comparison with conventional clutch mechanisms that
operate to limit the output torque of a transmission, these devices
can be typically operable over a relatively narrow torque band,
necessitating a change in their clutch spring if a considerable
shift in the magnitude of the output torque is desired. In
contrast, the clutch mechanism 18 of the present disclosure can
accommodate a considerable shift in the magnitude of the output
torque of the tool 10 by simply operating the transmission assembly
16 in a different (i.e., lower or higher) gear ratio.
In the operation of rotary power tools such as tool 10, it is
frequently desirable to change between two clutch settings, as when
the tool 10 is used to both drill a hole and thereafter install a
screw in that hole. Accordingly, the adjustment mechanism 704 may
be rotated relative to the output spindle assembly 20 to position
the adjustment mechanism 704 at a desired one of the adjustment
segments 772, 774 and 776 to perform the first operation and
thereafter rotated to a second one of the adjustment segments 772,
774 and 776 to perform the second operation. In contrast to the
known clutch arrangements, the adjustment mechanism 704 of the
present disclosure is configured such that the adjustment structure
760 and the setting collar 762 can be rotatable through an angle of
360.degree.. Assuming the adjustment structure 760 to be positioned
at an intermediate adjustment segment 776x, rotation of the
adjustment mechanism 704 through an angle of 360.degree. would
rotate the adjustment structure 760 past the other intermediate
adjustment segments 776, as well as the first and last adjustment
segments 772 and 774 and the ramp section 778 such that the
adjustment structure 760 would again be positioned at the
intermediate adjustment segment 776x. The feature is especially
convenient when it is necessary to change the clutch setting
between a relatively high clutch setting and a relatively low
clutch setting. In this regard, the ramp section 778 permits the
setting collar 762 (and adjustment structure 760) to be rotated
from highest clutch setting, corresponding to the last adjustment
segment, to the lowest clutch setting, corresponding to the first
clutch setting, without positioning the clutch mechanism 18 in one
of the intermediate clutch settings. Accordingly, the user of the
tool 10 is able to vary the clutch setting from its maximum setting
to its minimum setting (and vice versa) by rotating the setting
collar 762 a relatively small amount.
While the adjustment profile 770 has been described thus far as
having a constant slope, those skilled in the art will appreciate
that the disclosure, in its broader aspects, may be constructed
somewhat differently. For example, the adjustment profile 770' may
be formed such that each of the first, last and intermediate
adjustment segments 772', 774' and 776' is detented as illustrated
in FIG. 31. In this arrangement, the detents 782 in the adjustment
structure 760 and the follower 780 in the housing portion 766 of
the output spindle assembly 20 can be unnecessary as the adjustment
segments 772', 774' and 776' will cooperate with the engagement 702
to provide the user of the tool 10 with a tactile indication of the
position of the adjustment profile 770', as well as inhibit the
free rotation of the adjustment structure 760.
Another example is illustrated in FIG. 32 wherein the adjustment
profile 770'' is generally similar to the adjustment profile 770
except that the ramp section 779 has been omitted so that the last
intermediate adjustment segment 776z is immediately adjacent the
last adjustment segment 774.
While the transmission assembly 16 has been described thus far as
including a three-stage, three speed transmission, those of
ordinary skill in the art will appreciate from this disclosure that
the disclosure, in its broader aspects, may be constructed somewhat
differently. For example, another (i.e., fourth) or different speed
ratio may be provided by operating two of the reduction gear sets
(e.g., both the second and third reduction gear sets 304 and 306)
in the inactive mode. Those of ordinary skill in the art will also
appreciate from this disclosure that the second reduction gear set
304 may be placed in the inactive mode by coupling the second ring
gear 360 to the second planet carrier 364 (rather than to the first
planet carrier 314) and/or that the third reduction gear set 306
may be placed in the inactive mode by coupling the third ring gear
400 to the second planet carrier 364 (rather than to the third
planet carrier 404).
Other transmission assemblies constructed in accordance with the
teachings of the present disclosure are illustrated in FIGS. 33
through 56. Generally speaking, these configurations are similar to
that which is described above and illustrated in detail in FIGS. 23
through 25. Accordingly, similar or corresponding elements of the
alternately constructed transmission assemblies are identified by
similar reference numerals as were used to describe the
transmission assembly 16.
In the example of FIGS. 33 through 35, the transmission assembly
16-1 may include one or more movable elements which may be employed
to selectively couple the ring gears 360-1 and 400-1 of the second
and third reduction gear sets 304-1 and 306-1, respectively, to the
transmission sleeve 200-1. The movable elements, which may be pins
2000 and 2002, may be housed in the transmission sleeve 200-1 and
extend through corresponding apertures 2004 and 2006, respectively,
in the transmission sleeve 200-1 and may be translated into and out
of engagement with a respective one of the ring gears (i.e., ring
rears 360-1 and 400-1). In the example provided, each of the ring
gears 360-1 and 400-1 can include teeth 370-1 and 418-1,
respectively, (similar to teeth 370 and 418, respectively, that are
shown in FIG. 23) that are spaced apart by a sufficient distance to
receive the pins 2000 and 2002, respectively, therebetween. With
the ring gears 360-1 and 400-1 locked to the transmission sleeve
200-1 as shown in FIG. 33, the transmission assembly 16-1 operates
in a manner that is similar to that which is described in
conjunction with FIG. 23, above.
In FIG. 34, the transmission assembly 16-1 is shown in a second
overall speed or gear reduction ratio, wherein the first and second
reduction gear sets 302-1 and 304-1 are in an active condition and
the third reduction gear set 306-1 is in an inactive condition. The
third reduction gear set 306-1 may be inactivated by moving (e.g.,
translating) the pin 2002 out of engagement with the teeth 418-1 of
the ring gear 400-1 and engaging the third planet carrier 404-1 to
the third ring gear 400-1. This latter task may be accomplished,
for example, by sliding the third planet carrier 404-1 toward and
into engagement with the third ring gear 400-1. Any appropriate
means may be employed to engage the third planet carrier 404-1 and
the third ring gear 400-1 to one another, including friction (i.e.,
frictional engagement), or features, such as pins or teeth, that
may be formed on one or both of the third planet carrier 404-1 and
the third ring gear 400-1. In the example provided, teeth 2010,
which are formed on the third ring gear 400-1, engage mating teeth
2012 that are formed on the planet carrier 404-1.
In FIG. 35, the transmission assembly 16-1 is shown in a third
overall speed or gear reduction ratio, wherein the first and third
reduction gear sets 302-1 and 306-1 are in an active condition and
the second reduction gear set 304-1 is in an inactive condition.
The second reduction gear set 304-1 may be inactivated by moving
(e.g., translating) the pin 2000 out of engagement with the teeth
370-1 of the ring gear 360-1 and engaging the first planet carrier
314-1 to the second ring gear 360-1.
This latter task may be accomplished, for example, by sliding the
first planet carrier 314-1 toward and into engagement with the
second ring gear 360-1. Any appropriate means may be employed to
engage the first planet carrier 314-1 and the second ring gear
360-1 to one another, including friction (i.e., frictional
engagement), or features, such as pins or teeth, that may be formed
on one or both of the first planet carrier 314-1 and the second
ring gear 360-1. In the example provided, teeth 2014, which are
formed on the second ring gear 360-1, engage mating teeth 2016 that
are formed on the first planet carrier 314-1.
Those skilled in the art will appreciate that although the movable
elements (e.g., pins 2000 and 2002) have been illustrated as
translating in a direction that is generally perpendicular to the
longitudinal axis of the transmission assembly 16-1, the disclosure
in its broadest aspects, however, may be configured somewhat
differently. For example, each of the movable elements may be
translated in a direction that is generally parallel to the
longitudinal axis of the transmission 16-1 between a first
position, which permits the movable element to engage a feature on
a respective one of the ring gears, and a second position, which
aligns the movable element to an annular groove or a smooth,
featureless portion on the respective ring gear so that the movable
element does not inhibit the rotation of the respective ring
gear.
The transmission assembly 16-2 of FIGS. 36 through 38 is generally
similar to the embodiment of FIGS. 33 through 35, except that the
first set of planet gears 344 of the first reduction gear set 302-2
and the third set of planet gears 402 of the third reduction gear
set 306-2 remain in a fixed position relative to the first and
third ring gears 310 and 400-1, respectively, regardless of the
position of the first and third planet carriers 314-2 and 404-2,
respectively. In contrast, the first set of planet gears 344 and
the third set of planet gears 402 slide with the first and third
planet carriers 314-1 and 404-1, respectively, in the embodiment of
FIGS. 33 through 35.
With reference to FIGS. 39 through 41, the transmission assembly
16-3 may include one or more locking elements that may be
selectively employed to lock the second and third ring gears 360-3
and 400-3 to the first and third planet carriers 314-3 and 404-3,
respectively. The locking elements may include, for example first
and second idler gears 2050 and 2052, for example, that may have
teeth 2050a and 2052a, respectively, that may be meshingly engaged
to teeth 314a and 404a, respectively, that are formed on the first
and third planet carriers 314-3 and 404-3, respectively. The
locking elements 2050 and 2052 may be rotatably supported on pins
2054 and 2056, respectively, that may be mounted to another portion
of the power tool, such as the transmission sleeve 200-3. In a
first speed reduction ratio, which is illustrated in FIG. 39, the
second and third ring gears 360-3 and 400-3 are fixed to the
transmission sleeve 200-3, for example by teeth 370-3 and 418-3,
respectively, on the outer diameter of the ring gears 360-3 and
400-3, respectively, and mating teeth 254-3 and 256-3,
respectively, that are formed on the interior of the transmission
sleeve 200-3.
In FIG. 40, the transmission assembly 16-3 is shown in a second
overall speed or gear reduction ratio, wherein the first and second
reduction gear sets 302-3 and 304-3 are in an active condition and
the third reduction gear set 306-3 is in an inactive condition. The
third reduction gear set 306-3 may be inactivated by translating
the third ring gear 400-3 such that the teeth 418-3 are not engaged
with the mating teeth 256-3 on the transmission sleeve 200-3 but
rather with the teeth 2052a of the second idler gear 2052.
Translation of the third ring gear 400-3 may also cause the third
planet carrier 404-3 to slide on the second idler gear 2052 and/or
the third set of planet gears 402 to slide relative to the
transmission sleeve 200-3.
In FIG. 41, the transmission assembly 16-3 is shown in a third
overall speed or gear reduction ratio, wherein the first and third
reduction gear sets 302-3 and 306-3 are in an active condition and
the second reduction gear set 304-3 is in an inactive condition.
The second reduction gear set 304-3 may be inactivated by
translating the second ring gear 360-3 such that the teeth 370-3
are not engaged with the mating teeth 254-3 on the transmission
sleeve 200-3 but rather with the teeth 2050a of the first idler
gear 2050. Translation of the second ring gear 360-3 may also cause
the first planet carrier 314-3 to slide on the first idler gear
2050 and/or the first set of planet gears 344 to slide relative to
the transmission sleeve 200-3.
With reference to FIGS. 42 through 44, the transmission assembly
16-4 may be configured such that portions of the second reduction
gear set 304-4 and the third reduction gear set 306-4 may slide
into and out of locking engagement with another element of the
transmission assembly 16-4. In the example provided, the second and
third sets of planet gears 382-4 and 402-4, respectively, may be
translated between a first position, in which they meshingly engage
an associated ring gear, and a second position, in which they
non-rotatably engage an associated planet carrier as well as
meshingly engage the associated ring gear. In a first speed
reduction ratio, which is illustrated in FIG. 42, the second and
third ring gears 360-4 and 400-4 are fixed to the transmission
sleeve 200-4, in a manner that is similar to that which was
described above in conjunction with FIG. 33.
In FIG. 43, the transmission assembly 16-4 is shown in a second
overall speed or gear reduction ratio, wherein the first and second
reduction gear sets 302-4 and 304-4 are in an active condition and
the third reduction gear set 306-4 is in an inactive condition. The
third reduction gear set 306-4 may be inactivated by translating
the pin 2002 out of engagement with the teeth 418-1 on the third
ring gear 400-4 and translating the third set of planet gears 402-4
into engagement with the third planet carrier 404-4 such that the
third set of planet gears 402-4 are maintained in a stationary
condition relative to the third planet carrier 404-4. Engagement of
the third set of planet gears 402-4 to the third planet carrier
404-4 may be made in any desired manner, such as frictional
engagement or through mating features. In the example provided,
teeth 2076 are formed into an axial end face of the third set of
planet gears 402-4 and mating teeth 2078 are formed on the third
planet carrier 404-4 which meshingly engage the teeth 2076 on the
third set of planet gears 402-4. The third ring gear 400-4 may
optionally translate with the third set of planet gears 402-4.
In FIG. 44, the transmission assembly 16-4 is shown in a third
overall speed or gear reduction ratio, wherein the first and third
reduction gear sets 302-4 and 306-4 are in an active condition and
the second reduction gear set 304-4 is in an inactive condition.
The second gear set 304-4 may be inactivated by translating the pin
2000 out of engagement with the teeth 370-1 of the second ring gear
360-4 and translating the second set of planet gears 382-4 into
engagement with the first planet carrier 314-4 such that the second
set of planet gears 382-4 are maintained in a stationary condition
relative to the first planet carrier 314-4. Engagement of the
second set of planet gears 382-4 to the first planet carrier 314-4
may be made in any desired manner, such as frictional engagement or
through mating features. In the example provided, teeth 2072 are
formed into an axial end face of the second set of planet gears
382-4 and mating teeth 2074 are formed on the first planet carrier
314-4 which meshingly engage the teeth 2072 on the second set of
planet gears 382-4. The second ring gear 360-4 may optionally
translate with the second set of planet gears 382-4.
In FIGS. 45 through 47 yet another transmission assembly 16-5
constructed in accordance with the teachings of the present
disclosure is illustrated. The transmission assembly 16-5 may
include movable elements, such as pins 2000 and 2002, which may be
employed to lock the second and third ring gears 360-5 and 400-5,
respectively, in a stationary position, and locking elements, such
as first and second idler gears 2050-5 and 2052-5, respectively,
that may be employed to lock each of the second and third ring
gears 360-5 and 400-5, respectively, to the first and third planet
carriers 314-5 and 404-5, respectively. With specific reference to
FIG. 45, the transmission 16-5 is illustrated in a first overall
speed reduction or gear ratio wherein the pins 2050-5 and 2052-5
may be positioned in engagement with teeth 370-1 and 418-1,
respectively, on the second and third ring gears 360-5 and 400-5,
respectively, to maintain the second and third ring gears 360-5 and
400-5 in a stationary position. In this condition, the first and
second idler gears 2050-5 and 2052-5 may be disengaged from the
teeth 370-1 and 418-1 of the second and third ring gears 360-5 and
400-5, respectively, as well as from the teeth 314a and 404a of the
first and third planet carriers 314-5 and 404-5.
In FIG. 46, the transmission assembly 16-5 is illustrated in a
second overall speed reduction or gear ratio wherein the first and
second reduction gear sets 302-5 and 304-5, respectively, are in an
active condition and the third reduction gear set 306-5 is in an
inactive condition. The third reduction gear set 306-5 may be
inactivated by translating the pin 2002 out of engagement with the
teeth 418-1 of the third ring gear 400-5 and moving the idler gear
2052-5, e.g., by translation and/or rotation, into a position where
the teeth 2052a of the idler gear 2052-5 meshingly engage both the
teeth 418-1 of the third ring gear 400-5 and the teeth 404a of the
third planet carrier 404-5.
In FIG. 47, the transmission assembly 16-5 is illustrated in a
third overall speed reduction or gear ratio wherein the first and
third reduction gear sets 302-5 and 306-5 are in an active
condition and the second reduction gear set 304-5 is in an inactive
condition. The second reduction gear set 304-5 may be inactivated
by translating the pin 2000 out of engagement with the teeth 370-1
of the second ring gear 360-5 and moving the idler gear 2050-5,
e.g., by translation and/or rotation, into a position where the
teeth 2050a of the idler gear 2050-5 meshingly engage both the
teeth 370-1 of the second ring gear 360-5 and the teeth 314a of the
first planet carrier 314-5.
In FIGS. 48 through 50 yet another transmission assembly 16-6
constructed in accordance with the teachings of the present
disclosure is illustrated. The transmission assembly 16-6 may
include movable elements, such as idler gears 2050-6 and 2052-6
which may be employed to lock the ring gears 360-6 and 400-6,
respectively, into a stationary position relative to the
transmission sleeve 200-6 or to lock the second and third ring
gears 360-6 and 400-6 for rotation with the first and third planet
carriers 314-6 and 404-6, respectively. With specific reference to
FIG. 48, the transmission assembly 16-6 is illustrated in a first
overall speed reduction or gear ratio wherein the idler gears
2050-6 and 2052-6 are positioned to maintain the second and third
ring gears 360-6 and 400-6 in a stationary position. The idler
gears 2050-6 and 2052-6 may engage a feature, such as teeth 2090
and 2092, respectively, that is formed on another part of the power
tool, such as the housing 12-6 or the transmission sleeve 200-6,
which inhibits their rotation and thereby locks a respective one of
the ring gears in a stationary position.
In FIG. 49, the transmission assembly 16-6 is illustrated in a
second overall speed reduction or gear ratio wherein the first and
second reduction gear sets 302-6 and 304-6 are in an active
condition and the third reduction gear set 306-6 is in an inactive
condition. The third reduction gear set 306-6 may be inactivated by
translating the idler gear 2052-6, e.g., along the journal pin
2096, into a position where the teeth 2052a of the idler gear
2052-6 do not engage the tooth or teeth 2092 but engage both the
teeth 418-1 of the third ring gear 400-6 and the teeth 404a of the
third planet carrier 404-6.
In FIG. 50, the transmission assembly 16-6 is illustrated in a
third overall speed reduction or gear ratio, wherein the first and
third reduction gear sets 302-6 and 306-6 are in an active
condition, and the second reduction gear set 304-6 is in an
inactive condition. The second reduction gear set 304-6 may be
inactivated by translating the idler gear 2050, e.g., along the
journal pin 2096, into a position where the teeth 2050a of the
idler gear 2050-6 do not engage the tooth or teeth 2090 but engage
both the teeth 370-1 of the second ring gear 360-6 and the teeth
314a of the first planet carrier 314-6.
In FIGS. 51 through 53 a further transmission assembly 16-7
constructed in accordance with the teachings of the present
disclosure is illustrated. The transmission assembly 16-7 may
include movable, intermediate locking elements, such as collars
3000 and 3002, which may be employed to lock the second and third
ring gears 360-7 and 400-7 in a stationary position or for rotation
with the first and third planet carriers 314-7 and 404-7,
respectively. With specific reference to FIG. 51, the transmission
16-7 is illustrated in a first overall speed reduction or gear
ratio wherein the collars 3000 and 3002 are positioned to maintain
the second and third ring gears 360-7 and 400-7 in a stationary
position. The collars 3000 and 3002 may engage the teeth 370-1 and
418-1 of the second and third ring gears 360-7 and 400-7 and may
include features, such as teeth or pins 3004 and 3006,
respectively, that may engage a mating feature, such as teeth or
apertures 3008, that may be formed into another portion of the
power tool, such as the transmission sleeve 200-7, to thereby lock
a respective one of the ring gears in a stationary position.
Alternatively, the pins 3004 and 3006 of the collars 3000 and 3002,
respectively, may extend through apertures (not shown) that can be
formed in the second and third ring gears 360-7 and 400-7,
respectively.
In FIG. 52, the transmission assembly 16-7 is illustrated in a
second overall speed reduction or gear ratio wherein the first and
second reduction gear sets 302-7 and 304-7 are in an active
condition and the third reduction gear set 306-7 is in an inactive
condition. The third reduction gear set 306-7 may be inactivated by
translating the collar 3002 into a position where the pins 3006
disengage the apertures 3008 in the transmission sleeve 200-7 and
the collar 3002 engages both the teeth 418-1 of the third ring gear
400-7 and the third planet carrier 404-7. Any appropriate means may
be employed to engage the collar 3002 and the third planet carrier
404-7 to one another, including friction (i.e., frictional
engagement), or features, such as pins or teeth, that may be formed
on one or both of the third planet carrier 404-7 and the collar
3002. In the example provided, the collar 3002 frictionally engages
the planet carrier 404-7.
In FIG. 53, the transmission assembly 16-7 is illustrated in a
third overall speed reduction or gear ratio wherein the first and
third reduction gear sets 302-7 and 306-7 are in an active
condition and the second reduction gear set 304-7 is in an inactive
condition. The second reduction gear set 304-7 may be inactivated
by translating the collar 3000 into a position where the pins 3004
disengage the apertures 3008 in the transmission sleeve 200-7 and
the collar 3000 engages both the teeth 370-1 of the second ring
gear 360-7 and the first planet carrier 314-7. Any appropriate
means may be employed to engage the collar 3000 and the first
planet carrier 314-7 to one another, including friction (i.e.,
frictional engagement), or features, such as pins or teeth, that
may be formed on one or both of the first planet carrier 314-7 and
the collar 3000. In the example provided, the collar 3000
frictionally engages the first planet carrier 314-7.
The embodiment of FIGS. 54 through 56 is generally similar to that
of FIGS. 51 through 53, except that each of the collars 3000-8 and
3002-8 can include teeth 3050 and 3052, respectively, that
meshingly engage the teeth 370-8 and 418-8, respectively, that can
be formed on the second and third ring gears 360-8 and 400-8,
respectively. As shown in FIG. 56, the collar 3000-8 may be
translated into a position where the teeth 3050 meshingly engage
both the teeth 370-8 of the second ring gear 360-8 and the teeth
314a of the first planet carrier 314-8 to thereby place the second
reduction gear set 304-8 into the inactive mode. Similarly, the
collar 3002-8 may be translated into a position where the teeth
3052 engage both the teeth 418-8 of the third ring gear 400-8 and
the teeth 404a of the third planet carrier 404-8 to thereby place
the third reduction gear set 306-8 into the inactive mode as is
shown in FIG. 55.
While the disclosure has been described in the specification and
illustrated in the drawings with reference to various embodiments,
it will be understood by those skilled in the art that various
changes may be made and equivalents may be substituted for elements
thereof without departing from the scope of the disclosure as
defined in the claims. Furthermore, the mixing and matching of
features, elements and/or functions between various embodiments is
expressly contemplated herein so that one of ordinary skill in the
art would appreciate from this disclosure that features, elements
and/or functions of one embodiment may be incorporated into another
embodiment as appropriate, unless described otherwise, above.
Moreover, many modifications may be made to adapt a particular
situation or material to the teachings of the disclosure without
departing from the essential scope thereof. Therefore, it is
intended that the disclosure not be limited to the particular
embodiment illustrated by the drawings and described in the
specification as the best mode presently contemplated for carrying
out this disclosure, but that the disclosure will include any
embodiments falling within the foregoing description and the
appended claims.
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